This will be my first non-J scp I've written, and may be the first I actually publish on the site if I can refine it enough. Here's its sandbox.
My main issue with it right now is that it's kind of excessively long, at least for what it is. If you have any suggestions and what to abbreviate or cut in order to make its length more appropriate, that would be awesome.
In terms of tone, I don't have a lot practice with this, so it's decently likely that I need to clean this up in a few places.
I'm not sure how helpful of necessary the addendum is, but I hope that I used it correctly?
In any case, feedback, is super appreciated.

A small colony of SCP-XXXX is maintained in a section of fertile soil measuring 5m in width, 10m in length, and three feet in depth

I know you go on to say in the next sentence that these things are kept in a containment chamber, but it might be good to outright state that here and then explain that it's also filled with dirt.

Area is to remain over 24/7 video surveillance to prevent possible containment breach

"Over" should be "under". Also, the bit about preventing containment breaches is implied by everything in the containment procedures so it can just be gotten rid of.

In the case of containment breach, all staff associated with SCP-XXXX are to be immediately detained to prevent aid of breach.

this part can also be omitted.

Farm was searched

should include a "The" before farm. Additionally, this paragraph might fit better if moved to after describing the effects of this SCP.

Upon visual or physical contact, SCP-XXXX’s secondary psychological effects begin to take place

I'll be honest, this secondary effect doesn't do much for me. I feel like the rest of the article spends a lot of time explaining how this progresses and what it does, but it feels a bit tacked on for the sake of making it be a problem (That being said, I did really love the phrase "immediate emotional response towards root vegetables").

However, I don't think this idea needs it to stand on its own. The idea of having colonies of these carrots (who are not only alive, but help each other and work together) is a really interesting one, and I'd really like to see how they might live together on a small plot of land in a containment facility.

In short, I feel like it's a really good idea that's only touched on before going for a more generic "thing what makes you compelled to do a thing" route. When I hear "colony of sentient carrots" I want to see what it is they do. Do they have a culture? Do they/could they build anything? How do they feel about the Foundation? Would they build little carrot houses to live in? This is just my opinion, but I think that ditching that secondary anomalous effect and just diving into what exactly these things are and how they function and live might make it this really shine.

Regardless, the potential is most certainly there, so I look forward to seeing it when it's done!

That totally makes sense, thank you! I've made the corrections you included.
As far as the secondary effect, I guess I mainly want to convey that these little dudes sustain themselves by using people as protectors? But I do think that I definitely put too much focus on that in this, and I'll likely tone down or omit the idea of people being ready to kill for them.
Hopefully I'll be able to work on expanding on colony structure and contracting the secondary effects during the coming week - thank you so much for your help on this!!